Question about Django. Assistance in the implementation of registration for the tournament. How to implement?

Question

Django

At the moment there are such models:

class Team(models.Model):
    name = models.CharField('Название', max_length=35, unique=True)
    tag = models.CharField('Тег', max_length=16, unique=True)
    about = models.TextField('О команду', max_length=500, null=True, blank=True)
    logo = models.ImageField('Лого', upload_to="teams_logo/", null=True)
    game = models.ForeignKey(
        Game, verbose_name='игра', on_delete=models.SET_NULL, null=True, blank=True
    )
    tournament = models.ManyToManyField('Tournaments', verbose_name='Турниры', blank=True)
    slug = models.SlugField(unique=True, blank=True, null=True)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("team_detail", kwargs={"slug": self.slug})

    def save(self, *args, **kwargs):
        self.slug = slugify(self.name)
        super(Team, self).save(*args, **kwargs)

    class Meta:
        verbose_name = "Команда"
        verbose_name_plural = "Команды"

class Tournaments(models.Model):
    name = models.CharField('Название турнира', max_length=50)
    description = models.TextField('Описание турнира')
    prize = models.TextField('Призовой')
    game = models.ForeignKey(
        Game, verbose_name='Дисциплина', on_delete=models.CASCADE
    )
    author = models.ForeignKey(
        User, verbose_name='пользователь', on_delete=models.CASCADE, blank=True, null=True
    )
    teams = models.ManyToManyField(
        Team, verbose_name='Команда', blank=True
    )
    image = models.ImageField('Лого турнира')
    max_teams = models.PositiveSmallIntegerField('Максимальное количество команд', default=0)
    count_registration_teams = models.PositiveSmallIntegerField('Количество зарегестрированных команд', default=0)
    start_date = models.DateTimeField("Дата начала")
    start_registration_date = models.DateTimeField("Начало регистрации")
    end_registration_date = models.DateTimeField("Конец регистрации")
    slug = models.SlugField(unique=True, blank=True, null=True)
    status = models.BooleanField('Статус активности', default=False)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("tournament_detail", kwargs={"slug": self.slug})

    def save(self, *args, **kwargs):
        self.slug = slugify(f'{self.name} - {self.game}')
        super(Tournaments, self).save(*args, **kwargs)

    def get_tournament(self):
        return self.tournamentregistration_set

    class Meta:
        verbose_name = "Турнир"
        verbose_name_plural = "Турниры"


class TournamentRegistration(models.Model):
    tournaments = models.ForeignKey(Tournaments, on_delete=models.CASCADE)
    teams = models.ForeignKey(Team, on_delete=models.CASCADE, null=True, blank=True)
    user = models.ForeignKey(
        User, verbose_name='пользователь', on_delete=models.CASCADE, blank=True, null=True
    )

I don't really know if TournamentRegistration is required here at all. But there are thoughts only through him and the new form.

And there is this views:

class TournamentsRegistration(LoginRequiredMixin, View):

    def post(self, request, pk, *args, **kwargs):
        print(f'TYT ----> {request.POST} & {request.GET}<----')
        form = TournamentsRegistrationForm(request.POST or None)
        tournaments = Tournaments.objects.get(id=pk)
        if form.is_valid():
            print("OK")
            form.save(commit=False)
            form.tournaments = tournaments
            form.teams = request.user.profile.team
            form.tournaments.count_registraion_teams += 1
            form.save()
        else:
            print('НЕВЕРНАЯ ФОРМА')
            print(form.errors)
            print(form.non_field_errors())
        return redirect(tournaments.get_absolute_url())

And forms:

class TournamentsRegistrationForm(forms.ModelForm):

    class Meta:
        model = TournamentRegistration
        fields = {'tournaments', 'teams', 'user'}

And the following html.

<div class="registered_teams">
  <div class="registered_teams">
    {{ tournaments.count_registration_teams }} / {{ tournaments.max_teams }}<br>
  </div>
  <div class="tournament-registration">
    <form action="{% url 'tournament_registration' tournaments.id %}" method="post">
      {% csrf_token %}
      <button type="submit">Зарегестрироваться</button>
    </form>
  </div>
</div>

The following is required, by pressing the registration button, the captain's team was added to the tournament, and the tournament was added to the team, for this I used M2M communication, it is also necessary that the counter of registered teams increase by one (it is also desirable to display the name of registered teams on the page) and that the button is blocked registration for the team that is already registered for this tournament, but most likely I can do it myself. But it seems to me that here you need to work with Tournaments and without forms.py. Perhaps someone can suggest a solution. Before that, I could only increase the team counter with the help of JS and block the button, but this is not entered into the database in any way, but only visually entered on the tournament page without linking TOURNAMENT - TEAM \ TEAM-TOURNAMENT. If additional information is required, I will provide \ add here.

At the moment I made only such a crutch, but I myself understand this, not what is necessary and true:

class TournamentsRegistration(LoginRequiredMixin, View):

    def get(self, request, pk):
        print(f'TYT ----> {request.POST} & {request.GET}<----')
        form = TournamentsRegistrationForm(request.POST or None)
        tournaments = Tournaments.objects.get(id=pk)
        context = {'tournaments': tournaments, 'form': form}
        return render(request, 'tournaments/tournaments_detail.html', context)

    def post(self, request, tournament_id, *args, **kwargs):
        print(f'TYT ----> {request.POST} & {request.GET}<----')
        form = TournamentsRegistrationForm(request.POST or None)
        tournaments = Tournaments.objects.get(id=tournament_id)
        if form.is_valid():
            print("OK")
            form.save(commit=False)
            form.tournaments = tournaments
            form.tournaments.teams.add(request.user.profile.team)
            form.user = request.user
            form.tournaments.count_registration_teams += 1
            request.user.profile.team.tournament.add(tournaments)
            form.save()
            print(form.tournaments.teams.all())
            print(form.tournaments.teams.filter(tournaments__teams__name=request.user.profile.team.name))
            return redirect(tournaments.get_absolute_url())
        else:
            print('НЕВЕРНАЯ ФОРМА')
        context = {
            'form': form,
        }
        return render(request, 'tournaments/tournaments_add.html', context)

But in this code, count_registration_teams does not work, the counter of registered teams.